WordPress at a glance
filter is not described

preprocess_comment filter-hook . WP 1.5.0

Filters a comment's data before it is sanitized and inserted into the database.

Usage

add_filter( 'preprocess_comment', 'filter_function_name_3469' );
function filter_function_name_3469( $commentdata ){
	// filter...

	return $commentdata;
}
$commentdata(array)
Comment data.

Changelog

Since 1.5.0 Introduced.
Since 5.6.0 Comment data includes the comment_agent and comment_author_IP values.

Where the hook is called

wp_new_comment()
preprocess_comment
wp-includes/comment.php 2209
$commentdata = apply_filters( 'preprocess_comment', $commentdata );

Where in WP core the hook is used WordPress

Usage not found.